Step 2: Cook Until Thickened
Set the pan over medium heat and stir constantly as it cooks. Continue until the mixture becomes thick and bubbly, forming a smooth paste.

Step 3: Cool Completely
Remove from heat and allow the paste to cool entirely to room temperature before proceeding.

Step 4: Cream Butter and Sugar
In a large mixing bowl, beat together 1 cup of softened unsalted butter and 1 cup of granulated sugar until pale, light, and fluffy.

Step 5: Blend in the Cooked Mixture
Add the cooled flour-milk paste to the butter-sugar mixture. Beat on medium-high speed for about 3–5 minutes, or until everything is fully combined, smooth, and whipped to a silky texture.

Step 6: Add Vanilla
Mix in 1 teaspoon of vanilla extract, beating until the flavor is evenly incorporated.

Step 7: Frost and Enjoy
Spread this creamy frosting generously over your favorite cakes or cupcakes — smooth, light, and absolutely delicious!